<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container {
            width: 100%;
            font-size: 20px;
            font-family: 楷体;
            overflow: hidden;
        }

        .left,
        .center {
            position: relative;/*相对定位 原本的位置不会被其他元素覆盖*/
            float: left;
            width: 150px;
            height: 200px;
            line-height: 200px;
        }

        .left {
            background-color: rgb(66, 24, 214);
        }

        .center {
            background-color: rgb(14, 173, 41);
        }

        .right {
            width: 100%;
            height: 200px;
            float: right;
            background-color: pink;
            margin-left: -300px;
        }

        .content {
            line-height: 200px;
            margin-left: 300px;
        }
    </style>
</head>

<body>
    <div class="container">
        <div class="left">左侧固定</div>
        <div class="center">中间固定</div>
        <div class="right">
            <div class="content">右边自适应</div>
        </div>
    </div>
</body>

</html>